I am a computer scientist working with brain data. I have some data from different brain regions, and the regions are called temporal cortex, parietal cortex, hippocampus and forebrain white matter. I want to show those regions on a brain image in a presentation.

The problem is, when I search the brain images online, I cannot find the regions my data mentions. The regions in the search results are usually called "lobe" rather than "cortex". And when I search for "forebrain white matter", the results are usually about "cerebral white matter". I am totally confused. Here are a few questions:

Are "cortex" and "lobe" the same thing? Or does cortex means gray matter while lobe contains both gray and white matter?

Does hippocampus contain gray and white matter? Or does it reside in the inner side of the temporal lobe, meaning it is in the white matter part of the temporal lobe?

Are "forebrain" and "cerebrum" the same thing?

Why is hippocampus considered part of the temporal lobe although it has the long side of it outside of the temporal lobe?

1 Answer
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"Lobe" refers to a section of the cerebral cortex, which is the outer part of the cerebrum. The cerebrum contains several structures, but the one that most people care about is the cerebral cortex, which is the 2-4 mm thick layer on the surface of the cerebrum. The cerebral cortex (or "cortex") is divided into several lobes, e.g. temporal lobe, occipital lobe. So, cortex and lobe are not the same thing, as the lobes subdivisions of the cortex as a whole. (See https://en.wikipedia.org/wiki/Cerebral_cortex)

The hippocampus is a region of the cortex in the temporal lobe. Therefore, it consists of gray matter. However, it is connected to several other structures by white matter (e.g. the fornix), and these structures are related to the hippocampus. (See https://en.wikipedia.org/wiki/Hippocampus#Anatomy)

$\begingroup$Sorry, I had a typo in the 4th question. It should say "hippocampus". Corrected.$\endgroup$
– user5054Aug 29 '16 at 8:19

$\begingroup$1) So, then, although "cortex" and "lobe" are different things, what my data means by "temporal cortex" is probably the same as "temporal lobe"?$\endgroup$
– user5054Aug 29 '16 at 9:08

$\begingroup$2) I did not know temporal cortex consists of gray matter. So, temporal lobe thickness is 2-4 mm since it is part of the cortex. How about the gray matter thickness?$\endgroup$
– user5054Aug 29 '16 at 9:10

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$\begingroup$@user5054 the cerebral cortex is composed of the gray matter; so thickness would be the same. However, cortex is not equivalent to gray matter. In the spinal cord, the organization is reversed (outer part is white matter). The term, "gray matter", IMO has relatively little significance nowadays because we can see the anatomy of the brain at a much higher resolution. So, while the organization does matter, the terms - gray/white matter per se convey little information.$\endgroup$
– WYSIWYGAug 29 '16 at 9:40